Previous research in this project investigated behavioral and neural bases of two changes in attentional processing in associative learning mediated by the amygdala central nucleus (CN): the potentiation of orienting to conditioned stimuli (CSs) paired with food unconditioned stimuli (USs), and the enhancement of CS associability that occurs when contingencies between the CS and other events are altered. The proposed research extends that work by investigating the relation of these attentional changes to other aspects of attention, and by continuing systems analysis of these functions. The project will use a variety of behavioral procedures, asymmetrical lesion techniques, transient, reversible inactivation procedures, and electrophysiological recording methods, with rat subjects, to address four specific aims. The first aim is to distinguish between CN-systems effects on the acquisition and expression of conditioned orienting and associability changes. The second aim is to examine cortical neural encoding of attentional changes in associative learning that depend on CN and its regulation of the basal forebrain cholinergic system. The third aim is to examine the roles of CN attentional systems in performance of selective attention tasks. The fourth aim is to examine cortical activity during performance of selective attention tasks. This research may provide a basis for new insights into cognitive functions of the amygdala, as well as the integration of cognitive and emotional function. In addition, it may have wide clinical implications, because the neural systems to be studied are involved in a number of pathological conditions, for example, Alzheimer's disease (learning and attention deficits often signal the onset of more complete dementia), schizophrenia (deficits in focusing attention on relevant events and ignoring extraneous events), and various affective disorders (inappropriate assignment of motivational value to life events).